One cool thing about Zelda is how the incoorporate different graphic styles into each game they make. Even me, being completley biased to cell shaded graphics, recognizes this.
Like others have said it was a WiiU tech demo to get people psyched for not only Nintendo's leap into the HD universe but also to get people thinking about how the next Zelda will look. Personally I'll always like the cell shaded type stuff a lot more then the realistic stuff. I feel, though, that the next Zelda we'll see on the WiiU will be more realistic like Twilight Princess. One because first there was WW, cell shaded, then there was TP, realistic, then SS which leans more towards cell shaded then realistic. See a pattern? It's time for realistic Zelda to shine in the light once again.
I think realistic graphics just suits HD better anyways. Alsom the rest of the companys shine in realistc graphics such as Skyrim and Uncharted 3, and I think Nintendo is conforming with the crowd a bit here too since they're considered the graphic underdogs of the gaming world and they want to prove others wrong.